High speed printer

ABSTRACT

Type characters arranged in columns on a rotatably driven print drum of a high speed printer are selectively impacted by print hammers which are pivotally supported for striking the print drum. Each column of type characters defines a print position along a print line, and the number of print hammers is only a fraction of the number of print positions along the print line. To enable type characters to be printed at each print position, the print hammers are disposed for movement in slots provided in a guide member which is movable parallel to the print line to flex the print hammers sideways to impact type characters of adjacent columns on the print drum.

United States Patent 1191 Decker et a].

11] 3,797,387 [451 Mar. 19, 1974 HIGH SPEED PRINTER [75] Inventors: Herbert Decker, Lauf; Friedrich Jung, Tennenlohe, both of Germany [73] Assignee: Triumph Werke'Nuernberg A.G.,

Nuernbe'rg, Germany [22] Filed: Aug. 30, 1972 21 App]. No.: 284,741

[30] Foreign Application Priority Data Sept. 10, 1971 Germany 2145245 52] US. (:1 ..l 101/93 (3 [51] Int. Cl B4lj 5/14 [58] Field of Search 4101/9319, 111; 197/l,53

[56] 7 References Cited UNITED STATES PATENTS 3.433.153 3/1969 Harrington et al 101/93 C 3236.351 1 2/1966 Fitch et all 197/1 R 3.587.456 6/l97l Jaensch.... 101/93 C 3.308.749

3/1967 Do'wd.... 1 01/93 c Primary Examiner-Robert E. Pulfrey Assistant ExaminerE. M. Coven [5 7] ABSTRACT Type characters arranged in columns on a rotatably driven print drum of a high speed printer are selectively impacted by print hammers which are pivotally supported for striking the print drum. Each column of type characters defines a print position along a print line,and the number of print hammers is only a fraction of the number of print positions along the print line. To enable type characters to be printed at each printposition, the print hammers are disposed for movement in slots provided in a guide member which is movable parallel to the print line to flex the print hammers sideways to impact type characters of adjacent columns on the print drum.

4 Claims, 3 Drawing Figures HIGH SPEED PRINTER This invention relates to a high speed printer, and more particularly to a high speed printer wherein printing is effected by a print hammers impacting a recording medium against selected type characters carried on the periphery of a rotating drum.

In a high speed printer of the type wherein type characters are arranged in columns on the periphery of a rotatable type drum, each column defines a print position along a print line and means must be provided for impacting a recording medium against a selected type character at each print position. In the past, this was usually accomplished by providing a separate print hammer at each print position along the line of print. However, such an arrangement requires a large number print hammers and corresponding actuating mechanisms which are expensive and occupy a considerable amount of space in the printer.

To minimize both the size and cost of the printer, attempts have been made to reduce the number of print hammers necessary to print at each of the print positions along the print line. Such attempts are shown, for example in German Pat. No. 1,247,053 and in U. S. Pats. Nos. 3,433,153-and 3,220,343 or Re. Patent No. 26,240. In one attempt, the type-characters are arranged in columns on a rotatably driven drumin circumferentially staggered rows, and impact was effected by print hammers which spanned more than one column. However, such an arrange rnent is undersirable because it necessitates a drum having a larger diameter to accommodate, adjacent butstaggered columns of type, and to print a lineof type in the same amount of time required that the print drum be driven at a faster peripheral speed. However, the faster peripheral speed of the drum reduces the amount of time available to impact a selected type character and tends to cause printed characters to be blurred. Furthermore, the wider print hammer tends to tip when striking a type character, particularly if thetype character is in one of the outermost columns spanned by the print hammer, and such tipping further reduces the quality of the printed character. In addition, a print hammer spannin g a plurality of columns necessarily has a larger mass making it more difficult to move quickly to achieve a high rate of, printing. I

In another attempt to reduce the number of print hammers, the print hammers are pivotally mounted in a member which is movablefparallel to the print line for striking type characters at different print positions, and the actuating mechanisms for each of the various print hammers are pivotally supported to follow the movement of the print hammers along the print line. However, such a complicated mounting arrangement for the print hammers involves the movement of a relatively large mass.

Accordingly, an objectof the present invention is to minimize the number of print hammers in a high speed printer having type characters arranged on a rotatably driven drum without increasing the mass of the print hammers and without increasing the peripheral speed of the rotating drum. 1

Another object of the invention is to provide a high speed printer having print hammers for impacting a recording medium at a greater number of print positions along a print line, but without necessitating a complicated hammer mounting arrangementor hammer actuating arrangement which must be moved along the FIG. is a top view of a printer shown in FIG. 1 and illustrating the manner in which the print hammers are positioned relative to the type characters on the rotatably driven drum; and

FIG. 3 is a sectional view of the: printer taken along the lines 3-3 of FIG. 1.

Referring now in detail to the figures in the drawings, there is shown ahigh speed printer, generally indicated 11, for printing type characters on a recording medium 13 which may desirably be a strip of paper. The recording paper 13 is advanced incrementally through the nip of a pair of cooporating feed rollers 15, 17 respectively, along a guide chute, generally indicated at 19, and between a type element in the form of a rotatably driven print drum 21 and a series of print hammers, generally indicated 23, for printing at a print line. A suitable inked ribbon 25 may be located on either side of the recording paper 13, as is conventional, and printing is effected by impacting a print hammer 23 against the print drum 21 to press the inked ribbon25 and the recording paper 13 against a selected type character 27. The print hammer 23 isimpacted against the print drum 2], by energizing an electromagnetic actuating means, generally indicated 29, with a print signal to pull an interposer member 31 into engagement with a rotating cam 33 to drive the print hammer 23toward the rotating print drum 21. After a line is printed, the recording paper 13 and the ribbon 25 may be advanced in a conventional manner for further printing. Means for driving the feed rollers 15,17, the print drum 21, and the cam 33 as well as means for energizing the electromagnetic actuating means are not shown since they form no part of the present invention and may be desirably conventional.

As shown, each of the type hammers 23 are pivotally supported on a shaft 35 in front of the print drum 21, and havean arm 37 extending beneath the rotatably driven cam33 and into engagement with rearward portion 31a of the interposer member 31. The interposer member 31 is positioned in a guide comb 39 and resiliently biased rearwardly by means of a spring 41 stretched betweentheguide comb 39 and a projection 31b formed on the interposer member 31. The opposite end 310 of the interposer member 31 extends forwardly of the print hammer 23 and is supported in slots of another guide comb 43 adjacent the electromagnetic actuating means 29 for operating the print hammer 23. As shown, the print hammer 23 is maintained at a rest position by the urging of another resilient biasing means in the formof another spring 45 stretched between the print hammer 23 and the guide comb 43. In the rest position, the arm 37 of the print hammer 23 engages the rearward portion 3la of the interposer member 31.

When it is desired to operate the printer to print a selected type character on the recording paper 13, a print signal is supplied to the electromagnetic actuating means 29 in timed relation to the rotational movement of the selected type character 27 to energize the actuating means 29. Upon energization, the actuating means 29 pulls the interposer member 31 forwardly into engagement with the rotatably driven cam 33 whereupon a projection 33a of the cam 33 engages the rearward portion 31a of the interposer member 31 and drives it downwardly. At the same time, the arm 37 of the print hammer 23 is driven downwardly to pivot the print hammer 23 toward the print drum 21 to impact the ribbon 25 and paper 13 against the selected type character 27. After printing has been effected, the electromagnet 29 is deenergized and the print hammer 23 is returned to the rest position by the urging of the stretched spring 45. Concurrently, the interposer member 31 is urged rearwardly by the spring 41 in preparation for printing another type character.

As more particular shown in FIG. 2, the type characters 27 carried on the periphery of the print drum 2] are arranged in columns and rows with each column serving to define a print position on the print line. Located in front of the print drum 21 are the series of print hammers 23, each having a width substantially equal to the width of the type characters 27 arranged in columns on the print drum. Since printing is effected by the recording paper being impacted against a type character 27, it is apparent that means must be provided for effecting an impact at each print position on the print line, and in the past this was often accomplished by providing a separate print hammer for each print position on the print line.

In accordance with the present invention, the num ber of print hammers 23 necessary to print a line of type is significantly reduced by resiliently flexing the print hammers 23 about their pivotal support on the shaft 35 between two or more print positions on the print line. As more particularly shown in FIGS. 2 and 3, the print hammers 23 are guided during pivotal movement between the rest position and the print drum 21 by guide means, generally indicated 47. The guide means 47 is in the form of a guide-comb with a portion 49 of the print hammer 23 being received in slots 51 provided by the guide-comb 47. The guide means 49 may be suitably supported in substantially parallel relationship to the print drum 21 with one end connected to a suitable stationary support by resilient biasing means in the form of a spring 53 and with the other end connected to a suitable electromagnetic means which may be in the form of a solenoid, generally indicated 55.

In operation, printing along the print line is effected by operating the print hammers 23 with the guide means 47 at one'position to impact the recording paper against one set of print positions, and then shifting the position of the guide means 47 to enable the print hammers 23 to impact at another set of print positions. Normally, the print hammers 23 are located at fixed positions along the shaft 35 for impacting at one set of print positions. To impact another set of print positions, the solenoid'55 is energized to pull the guide means 47 along the print line against the urging of the spring 53. As the guide means 47 moves to another position, the print hammers 23 are flexed sideways in a direction transverse to their pivotal movement so as to position them for printing at another position, as shown in FIGS. 2 and 3. After printing in the other position, the solenoid 55 is deenergized and the guide means 47 is returned to the first position by the urging of the spring 53.

Although the printer 11 is shown and described with the print hammers 23 being flexed to print at only two sets of print positions, it is to be understood that the print hammers 23 may be flexed even further to effect printing at still another set of print positions, thus further reducing the number of print hammers necessary to print at all the print positions on the print line. Also, the solenoid 55 may be replaced by suitable cammin'g means for shifting the guide means 47 in alternately opposite directions thereby flexing the print hammers 23 to cover still more print positions thus further reducing the number of print hammers 23. In addition, the print hammers may be made movable on the shaft 35 parallel to the motion of the guide means 47 and may be moved by the guide means 47.

Furthermore, various arrangements of magnetic actuating means 29 are possible. For example, they may be staggered with respect to each other or be assembled in series or on one or both sides of the interposer member 31. Moreover, the print hammers 23 may be of either the pressure type hammer or the shock type hammer. Finally, invsome printers it may be advantageous to shift the print drum 21 relative to print hammers 23 which are not adjustable, or to even combine a shiftable print drum with adjustable print hammers.

While only a single embodiment of the present invention has been illustrated andde'scribed, it will be apparent to those skilled in the art that various modifications and improvements may be made without departing from the scope and spirit of the invention. Accordingly, it is to be understood that the invention is not to be limited by the illustrative embodiment, but only by the scope of the depending claims.

What is claimed is: I

1. In a printer having a plurality of print positions along a print line, the combination comprising:

a type element bearing a plurality of type characters and being supported for movement past a print line for presenting. type characters borne. thereon at said plurality of print positions,

a print hammer for impacting a recording medium against a selected type character on said type element at a print position of said print line,

said print hammer being pivotally supported for pivotal movement between a rest position and said type element, and

guide means for guiding the movement of said print hammer between said rest position and said print element,

said print hammer being resilient for flexing about its said pivotal support in a direction transverse to its pivotal movement,

said guide means being movable substantially along the print line for flexing said print hammer from one of said plurality of print positions to another of said print positions.

2. In a printer according to claim 1:

said type element bearing said plurality of type characters in at least two columns for movement past a print line and serving to define two print positions on the print lines, and

said print hammer having a width corresponding to substantially a single column of type characters for a cam supported for rotational movement for driving said print hammer to impact against a type character,

an electromagnetically actuated interposer means supported in engagement with said print hammer and operable in response to a print signal for engaging said cam to drive said print hammer to impact against a type character on said print drum,

guide means for guiding the movement of said print hammer to said print drum,

said print hammer being resilient about the pivotal support thereof in a direction transverse to its pivotal movement, and

said guide means being movable transversely to the pivotal movement of said print hammer for flexing said print hammer to impact against a type character in another column on said print drum.

4. In a printer according to claim 3:

said guide member being supported for movement substantially parallel to the print line to flex said print hammer for printing at one print position to another print position, and

another electromagnetic means operable in response to a signal to shift the print position of said print hammer for moving said guide member to' flex said print hammer from one print position to another print position. I 

1. In a printer having a plurality of print positions along a print line, the combination comprising: a type element bearing a plurality of type characters and being supported for movement past a print line for presenting type characters borne thereon at said plurality of print positions, a print hammer for impacting a recording medium against a selected type character on said type element at a print position of said print line, said print hammer being pivotally supported for pivotal movement between a rest position and said type element, and guide means for guiding the movement of said print hammer between said rest position and said print element, said print hammer being resilient for flexing about its said pivotal support in a direction transverse to its pivotal movement, said guide means being movable substantially along the print line for flexing said print hammer from one of said plurality of print positions to another of said print positions.
 2. In a printer according to claim 1: said type element bearing said plurality of type characters in at least two columns for movement past a print line and serving to define two print positions on the print lines, and said print hammer having a width corresponding to substantially a single column of type characters for impacting against a type character in only one of said two columns of type faces.
 3. In a printer, the combination comprising: a print drum supported for rotational movement and having type characters arranged in columns about the periphery for movement past a print line, a print hammer supported for pivotal movement to impact against a selected type character on one of said columns of type characters on said print drum, a cam supported for rotational movement for driving said print hammer to impact against a type character, an electromagnetically actuated interposer means supported in engagement with said print hammer and operable in response to a print signal for engaging said cam to drive said print hammer to impact against a type character on said print drum, guide means for guiding the movement of said print hammer to said print drum, said print hammer being resilient about the pivotal support thereof in a direction transverse to its pivotal movement, and said guide means being movable transversely to the pivotal movement of said print hammer for flexing said print hammer to impact against a type character in another column on said print drum.
 4. In a printer according to claim 3: said guide member being supported for movement substantially parallel to the print line to flex said print hammer for printing at one print position to another print position, and another electromagnetic means operable in response to a signal to shift the print position of said print hammer for moving said guide member to flex said print hammer from one print position to another print position. 